Distributed ledger systems (DLSs) enable participating entities to securely, and immutably store data. DLSs can also be referred to as consensus networks or blockchain networks, without referencing any particular use case. Examples of blockchain network can include consortium blockchain networks provided for a select group of entities. A consortium blockchain network can control the consensus process for the select group of entities. A consortium blockchain network includes an access control layer.
Smart contracts are programs that execute on blockchain networks. A smart contract contains a set of pre-defined rules under which the parties to that smart contract agree to interact with each other. In some instances, the smart contract running on the blockchain network requires input from outside of the blockchain network to evaluate pre-defined rules and perform corresponding actions. However, the smart contract itself cannot directly access external data sources. Consequently, a relay agent can be used to retrieve external data, and submit the data to the blockchain network for processing by the smart contract. This process, however, can result in security issues, such as potential attack vectors (e.g., distributed denial-of-service (DDoS) attacks).
Although techniques have been proposed for addressing security issues associated with data retrieval from external data sources, a more effective solution to address the security issues would be advantageous.